Flashcards
Spread Spectrum Technologies
Cards in this deck (20)
- 1Is 26 MHz wide. Is is known as the industrial band and part of this frequency range has already been allocated to the Global System for Mobile Communications (GSM)900MHz
- 2It is 100 MHz wide, is known as the scientific band and is commonly used by microwave ovens, cordless home telephones, baby monitors, and wireless video cameras2.4GHz
- 3It is 150 MHz wide, is known as the medical band. Used by many of the same types of consumer products: Baby monitors Cordless telephones Cameras5Ghz
- 4 New PHY and MAC layer enhancements have the potential of accomplishing speeds of future W i-Fi frequencies Up to 7 Gbps Since these ultrahigh frequencies have difficulty penetrating through walls, the technology will most likely be used to provide bandwidth-intensive and short distance communications indoors60Ghz
- 5This RF transmission method Uses very little bandwidth to transmit the data that it is carrying Example: a narrowband radio might transmit data on 2 MHz of frequency space at 80 watts AM and FM radio stations areNarrowband
- 6Uses more bandwidth than is necessary to carry its data Takes the data that is to be transmitted and spreads it across the frequencies that it is using Example: a spread spectrum radio might transmit data over a 22 MHz frequency space at 100 milliwattsSpread spectrum
- 7This problem occurs when a reflected signal arrives at the receiving antenna after the primary signalMultipath Interference
- 8transmits data by using a small frequency carrier space Then hops to another small frequency carrier space and transmits data, then to another frequency, and so onFrequency Hopping Spread Spectrum
- 9On FHSS Instead of transmitting on one set channel or finite frequency space, an FHSS radio transmits on a sequence of subchannels called hops. must consist of at least 75 frequencies, 1 MHz wideHopping Sequence
- 10amount of time that the FHSS system transmits on a specific Frequency before it switches to the next frequency in the hop setDwell Time
- 11measurement of the amount of time it takes for the transmitter to change from one frequency to anotherHop Time
- 12was originally specified in the primary, or root, 802.11 standard and provides 1 and 2 Mbps RF communications using the 2.4 GHz ISM band. The data that is being transmitted is spread across the range of frequencies that make up the channel. Uses DQPSK to modulate the dignal Uses chiping for converting a single data bit into a sequenceDirect Sequence Spread Spectrum
- 13has similar properties to spread spectrum, such as low transmit power and using more bandwidth than is required to transmit data. uses binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) phase modulation for the lower ODFM data rates The higher OFDM data rates use 16-QAM and 64- QAM modulation Quadrature amplitude modulation (QAM) is a hybrid of phase and amplitude modulationOFDM
- 142.4Ghz channel spans from where to where?2.412 GHz ± 11 MHz (2.401 GHz to 2.423 GHz)
- 152.4GHz Channels are separated each one by:5Mhz
- 16What is the distance between the centers on the non overlapping 2.4Ghz Channels?25MHz
- 17introduced the capability of bonding together two 20 MHz channels to create a larger 40 MHz channel which effectively doubles the frequency bandwidth, meaning double the data rates that can be available.802.11n channel bonding
- 18When deploying a WLAN, it is important to have overlapping cell coverage for what reason:For roamming to occur
- 19Wireless communication is typically performed within a constrained set of frequencies known as a frequency band The previous concept can also be reffred as:bandwidth
- 20Changes in speed due to modulation and coding is known as data rates Also often referred to as data bandwidthThroughput
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- Informática y Comunicaciones Flashcards on Spread Spectrum Technologies, created by Hugo Castro Gould on 15/07/2022.
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- Hugo Castro Gould
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